Food is a powerful primary and secondary reinforcer, and obese persons find food more reinforcing than nonobese persons. In addition, obese persons may find alternatives to food less reinforcing than nonobese persons, providing a mechanism to understand why obese persons consume excess calories. The food deprivation that is associated with a calorie reduced diet may increase the reinforcing value of food, paradoxically making it more difficult for some obese persons to maintain the decreased caloric levels needed for weight loss and maintenance. This study is designed to test an innovative program for pediatric obesity based on behavioral economic theory that provides reinforcement for obese children for alternatives to their usual high-fat/low nutrient density eating, reduces access to intake of high-fat foods, and teaches parents to reduce behaviors that may increase the reinforcing value of high-fat foods. One hundred twenty obese children will be randomized to one of two groups, an innovative experimental treatment based on behavioral economic principles, and our standard family-based behavioral intervention program. Children will be followed through 2 years after randomization. Dependent measures will include body mass index, changes in percent overweight, changes in the eating and activity environment, parent control and restriction of food intake, child perception of dietary restriction, caloric and nutrient intake, physical activity, and the reinforcing value of noneating alternatives to high-preference, palatable high-fat/low nutrient density foods. This study will yield important information on new ways to treat pediatric obesity, minimizing dietary restriction and maximizing children learning healthier eating habits.